Bell 47G-4A N28938

Summary

On 22 January 2010 at about 17:09 local time, a Bell 47G-4A registered N28938, operated by Inland Crop Dusters Inc, was involved in an accident near Shafter, California, United States. One person was on board and one had minor injuries. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

22 January 2010 at 17:09

Classification

Accident

Location

Shafter, California, United States

Coordinates

35.4733, -119.2428

Aircraft

Bell 47G-4A

Registration

N28938

Category

Helicopter

Engines

1

Operator

Inland Crop Dusters Inc

Operating rule

Part 137: Agricultural

Purpose of flight

Aerial Application

Phase of flight

Not recorded

Route

Shafter → Shafter

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR10LA117

1 person had minor injuries.

The loss of a main rotor blade counterweight due to corrosion. Contributing to the accident was the failure of the operator to perform the initial and recurrent inspections required by a Service Bulletin to detect the corrosion in the counterweight.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

The pilot reported that he was maneuvering the helicopter to make an aerial application pass. At approximately 80 feet above ground level, he heard a muffled "crack/bang" and the helicopter immediately yawed and he experienced lateral vibrations in the cyclic. The pilot then initiated a forced landing with the shaking becoming more violent. The helicopter subsequently landed hard with the engine still running. The main rotor blades contacted and severed the tail boom, and the engine separated from its mounts. Postaccident examination of the helicopter revealed that a main rotor counterweight was missing. Examination of the broken counterweight rod end showed evidence of corrosion over approximately 45 percent of the diameter of the rod end. Maintenance records indicate that a Service Bulletin to inspect main rotor counterweight rods for pit corrosion had not been complied with. The Service Bulletin states that after an initial inspection of the main rotor counterweight rods, recurrent inspections should be accomplished every 300 hours of time in service.

Quoted verbatim from the NTSB record.